The present invention relates to an adjustable seat in general, and more particularly to an adjustable seat for use in a vehicle, particularly a motor vehicle, which is positionally adjustable frontwardly and rearwardly of the seat by means of a rack-and-pinion drive.
Adjustable seats of the above-mentioned type are already known and in widespread use. Usually, the seats of this type include a seat component which is supported, via guiding tracks and support tracks, on a base component which, in turn, is connected to or forms a pair of the bottom of the motor vehicle. In this environment, it is also already known to rigidly connect a toothed rack at least with one of the support rails, and to so arrange a pinion member as to mesh with the toothed rack during the rotation thereof with a driving shaft and to thereby displace the seat component relative to the base component.
In one conventional adjustable seat of this type which is disclosed in the U.S. Pat. No. 2,953,190, one support rail is rigidly connected with the lower part of the seat component at each of the lateral sides of the seat component and forms a part of a guide track assembly. In this conventional adjustable seat, one toothed rack is rigidly connected with each of the support tracks, and a separate pinion member meshes with each of the toothed racks, each of the pinions being arranged underneath the seat component, being mounted for rotation in a bracket which is connected to the bottom of the motor vehicle, and being driven in rotation by an electromotor via a worm gear transmission. The electromotor is connected with each of the pinion members via flexible shafts or similar connecting elements, the electric motor as well as the worm gear transmission being arranged underneath the lower part of the seat component in the region between the two guide track arrangements. So long as the above-mentioned drive performs to satisfaction, it presents a very simple, inexpensive and otherwise advantageous solution to the problem of displacing the seat. However, when the electromotor or the transmission malfunctions, the seat can no longer be adjusted so that, inasmuch as the seat component will usually be in an adjusted position which is disadvantageous as far as the position of the electromotor and that of the transmission are concerned, both the electromotor and the transmission will be accessible only with difficulties for repair or replacement purposes. For this reason, it is sometimes necessary to dismount or disassemble the entire seat or at least some of the constituent components thereof. This, of course, is very disadvantageous, particularly in view of the substantial time expenditure involved in at least partially dismounting the seat only in order to repair or replace rather inexpensive parts, such as the electromotor or the transmission.